This application relates to a rotating shaft mechanism and a foldable terminal device. The rotating shaft mechanism includes a rotating shaft base, a shaft cover assembly, a rotating shaft, a centrifugal part, and a limiting member. The shaft cover assembly is disposed on a side of the rotating shaft base in a thickness direction of the rotating shaft base, and an accommodating groove is disposed in the shaft cover assembly. The rotating shaft is rotatably disposed on the rotating shaft base. The centrifugal part is fixedly disposed at one end of the rotating shaft, and the centrifugal part deviates from an axis of the rotating shaft. The centrifugal part is rotatably disposed in the accommodating groove and is in clearance fit with the accommodating groove.